Light valves allow the production of an image via the control of an amount of light reflected by or transmitted through the light valve on a pixel-by-pixel basis. For example, a liquid crystal display utilizes a liquid crystal panel as a transmissive light valve to produce an image by controlling the passage of polarized light through the liquid crystal panel. Color may be produced, for example, by using the liquid crystal panel to selectively pass light through colored filters located in each pixel of the display. White light may be produced by passing light through all colored filters of a pixel, while colored light may be produced by controlling the passage of light through a subset of filters of a pixel.
A backlight or mirror may be used behind the liquid crystal panel (i.e. on an opposite side of the panel as a viewer) to provide a source of light for the liquid crystal panel. Therefore, when a viewer perceives light coming from a liquid crystal display, the viewer is actually looking at whatever is located behind the panel, such as a backlight or mirror. When pixels of a liquid crystal panel are displaying bright light, the panel is largely transparent to visible light at those pixels.